1. Field of the Invention
This invention relates to an ink jet recording apparatus, and, more particularly, it is concerned with a recording apparatus provided with an ink jet head which is generally called "full line multi-array orifice type head".
2. Description of the Prior Art
Of various recording systems which are known at present, the so-called "ink jet recording system" is regarded as highly useful in realizing various types of recording apparatus, such as printer, word processor, reproduction device, etc., because it belongs to a non-impact recording system which produces the least noise at the time of recording, and is capable of recording at a high speed and on a plain paper without necessity for any special fixing treatment. So far, various proposals have been made for this ink jet recording system, some are already commercialized after many improvements, and others are still under way towards practical use.
The ink jet recording system is to perform image recording by causing droplets of recording liquid (throughout the description in this specification, the liquid is called "ink") to fly, on various operating principles, onto the surface of a recording material such as paper, etc. An ink droplet producing device for use in such an ink jet recording system, i.e., an ink jet device, consists generally of an ink jet head to form the ink droplets and an ink feeding system to feed ink to the head.
As a type of the ink jet head, there is one that is generally called "a single orifice type" or "a semi-multi-orifice type" head having one to ten, or so, of the ink discharging orifices. This type of head is relatively simple in its construction, is easy to replace when the head is out of order or damaged, and is not so expensive as the other recording systems. In addition, since the ink feeding system for this type of ink jet head has a lesser number of ink discharge orifices, there is less consumption of ink. Thus, it can be constructed relatively simply by utilizing a simple cartridge tank or a single ink feeding pipe.
However, when using a different type of the ink jet head, generally called "full line multi-array orifice type head", capable of printing a line on paper almost instantaneously, the replacement work of the head is not easy thereby increasing possibility of trouble and damage occurring in some part of the head. Further, from the economic aspect, the replacement of the entire head is limited. Furthermore, when using the full line multi-array orifice type head, it is necessary to maintain constant a space interval between the head and the surface of the recording paper throughout its breadth during the recording operation. In order to attain this objective, there have so far been required high mechanical precision and assembly precision as well as complicated accessory mechanisms and troublesome measures for preventing ink contamination of the head and for protecting the head itself during stoppage of the recording apparatus.
In addition, the ink feeding system for this type of the ink jet head necessitates a large number of ink feeding pipes and an ink tank of a large capacity for uniform ink feeding to the entire head, because the ink discharging orifices should be provided in an extremely large number in this type of the ink jet head, which causes the ink consumption through the entire head to be much higher than in the aforementioned case. As the consequence of this, the overall construction of the device becomes inconveniently complex and large in size.